HomeMy WebLinkAboutMinimum Commercial Standards - COM Letters / Memos - 5/25/1993 GARY YANDO,DIRECTOR
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o a°u �► DEPARTMENT OF COMMUNITY DEVELOPMENT
o T z PLANNING -SOLID WASTE-UTILITIES
z� N Y Y BLDG. III • 426 W. CEDAR • P.O. BOX 578
of rasa �o SHELTON, WA 98584 • (206)427-9670
May 25, 1993
Pen-nit Consulting Services
10020 Main Street
Suit 114
Bellevue, WA 98004
RE: Belfair prop. right vicinity. Commercial Development. S t o r in w a t e r
management.
Dear PCS:
The County requires commercial development to meet the following minimum standards for site
drainage:
4.2 Runoff Quantity
All proposed projects must provide runoff quantity controls to achieve the following three
purposes unless exempted because of direct discharge to a regional facility or a major body of
water or because of negligible increase in runoff ( see 4.2.1, below)
1. Infiltrate at least the excess runoff volume generated by the proposed development for
the 2-year , 24-hour design storm, provided that.site conditions are appropriate and
ground water quality will not be impaired. Release any residual runoff from the 2-year,
24-hour design storm at no greater than 100% of the peak runoff rate for that storm for
existing site conditions.
2. If infiltration is precluded because of site conditions then detain and release runoff from
the 2-year, 24-hour design storm at no greater than 50% of the peak runoff rate for pre-
existing site conditions.
3. Detain and release runoff from the 10 and 100-year, 24-hour design storm at no greater
than 100% of the peak rate for existing site conditions.
If you have specific questions about stormwater facility design please contact Alan Tahja of the
Mason County Public Works Department. Please submit your plans to the address below,
ATTN: J. Manassee.
Elecycled
PCs
page 2
/RKetf H. assee, Planner
Department of Community Development